ZFS and disappearing glabels

[George Hartzell]

Eric writes:
 > On 12/31/2009 1:48 PM, George Hartzell wrote:
 > >
 > > I've set up a system as described here.
 > >
 > >    http://wiki.freebsd.org/RootOnZFS/ZFSBootPartition
 > >
 > > Using the 8.0 Release DVD and then csup'ing to RELENG_8 and
 > > rebuilding.
 > >
 > > I set it up with a single drive, the only change that I made was that
 > > after creating ad10s1a I glabeled it as disk0, then added
 > > /dev/label/disk0 to the pool.
 > >
 > > That worked great.
 > >
 > > Then I added a second larger drive, giving it an MBR, a bsd label, and
 > > an s1a partition that I glabeled as disk1.  I attached that to the
 > > pool and it resilvered happily.
 > >
 > > However, when I rebooted I found that the pool now consists of
 > > label/disk0 and ad12s1a.  I detached ad12s1a, relabeled it as disk1,
 > > and attached disk1 to the pool again.  It resilvered fine.  Running
 > > strings on /boot/zfs/zpool.cache shows /dev/label/disk0 and
 > > /dev/label/disk1.
 > >
 > > But, when I reboot I find I'm back to label/disk0 and ad12s1a.  At
 > > this point strings on zpool.cache lists /dev/label/disk0 and ad12s1a.
 > >
 > > I'd like to have the device independence of using labels, and am also
 > > worried about problems caused by the different "disk" sizes (since the
 > > glabeled partition is 512 bytes smaller).
 > >
 > > Any ideas what's going wrong?
 > >
 > > Thanks,
 > >
 > 
 > 
 > i ran into the same issues. every reboot i would have to fight to 
 > relabel the drive (on 7.2). I upgraded to 8 and used GPT for everything 
 > (and ZFS on root) and i have not had any issues. I would recommend going 
 > that route. You can still label the drives with labels.
 > 
 > This is the docs I followed:
 > 
 > http://wiki.freebsd.org/RootOnZFS/GPTZFSBoot/Mirror
 > 
 > Works great!

I'm running something like that on another machine, but can't on this
one.

The gory details include the fact that this is a mac pro.  It's EFI
firmware only does magic bios emulation if it sees an MBR formatted
disk and so setting things up via GPT won't work for me.  I did try it
using the link that you pointed to above and it wouldn't boot.  Tried
it via the apple's firmware "choose a boot disk by holding down the
option key" trick and via rEFIt.

g.